The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 8 |
| 3 | 24 |
| 4 | 69 |
| 5 | 200 |
| 6 | 576 |
| 7 | 1661 |
| 8 | 4793 |
| 9 | 13824 |
| 10 | 39875 |
| 11 | 115020 |
| 12 | 331776 |
| 13 | 957008 |
| 14 | 2760488 |
| 15 | 7962624 |
| 16 | 22968182 |
| 17 | 66251701 |
| 18 | 191102976 |
| 19 | 551236370 |
| 20 | 1590040836 |
| 21 | 4586471424 |
| 22 | 13229672881 |
| 23 | 38160980056 |
| 24 | 110075314176 |
| 25 | 317512149144 |
| 26 | 915863521339 |
| 27 | 2641807540224 |
| 28 | 7620291579446 |
[1,3,8,24,69,200,576,1661,4793,13824,39875,115020, 331776,957008,2760488,7962624,22968182,66251701, 191102976,551236370,1590040836,4586471424, 13229672881,38160980056,110075314176,317512149144, 915863521339,2641807540224,7620291579446] |